[TESTBUG] RandomCommandsTest must check if tested directive is added via jcmd

Running the following test:

$ make run-test TEST="compiler/compilercontrol/mixed/RandomCommandsTest.java" CONF=linux-x86_64-server-fastdebug TEST_VM_OPTS="-Djdk.test.lib.random.seed=3488255129154929879"

leads to the failure:

java.lang.RuntimeException: 'CompileCommand: An error occurred during parsing' missing from stdout/stderr